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There are few published reports of the results of supravalvular aortic stenosis correction with the use of Brom's 3-patch technique. Herein, we report our use of this procedure and the short-term results therefrom.
From 2002 through 2007, 9 children underwent surgical correction of localized supravalvular aortic stenosis at our hospital. The patients ranged in age from 5 to 14 years, and 8 had Williams syndrome. All operations were performed by the same surgical team.
No clinically significant associated cardiac anomalies were encountered. Each aortic repair involved the use of pericardium, Dacron, or both. One patient had an uncorrected right coronary artery obstruction and died postoperatively of refractory supraventricular tachycardia. In all 8 patients who survived, postoperative transaortic blood pressure gradients were improved (range, 0–16 mmHg), and no repeat operations were needed after 6 to 55 months' follow-up.
We consider Brom's technique to be safe in the repair of supravalvular aortic stenosis. In our limited series, it produced effective anatomic restoration, with good short-term and potentially good long-term results.
Supravalvular aortic stenosis (SVAS) is an uncommon but well-characterized congenital narrowing of the ascending aorta above the level of the aortic valve (Fig. 1).1 Most often, the narrowing is localized just above or at the most superior level of the attachments of the valve commissures, in association with some dilation of the sinuses of Valsalva and absence of poststenotic dilation. The aorta then looks like an hourglass. Less often, the narrowing extends diffusely throughout the ascending aorta and sometimes extends into the arch and the origins of the brachiocephalic artery. Supravalvular aortic stenosis occurs in 3 forms: sporadic; as part of Williams syndrome; or in a familial form that is transmitted as an autosomal dominant trait.2–4 The origin of SVAS is strongly suspected to depend on a quantitative reduction in elastin during development.2,5–6
Since the 1st successful repair in 1956, various surgical techniques for the relief of SVAS have been developed.4 Extended aortoplasty that enlarges the affected structures, as reported by Doty and colleagues,7 is most commonly used to treat the anomaly. Because this technique reconstructs only the right and noncoronary sinuses, the left sinus might still exhibit substantially distorted anatomy, with the risk of ischemia secondary to limited inflow into the left coronary artery.3,8 Steinberg and associates9 reported the cases of 3 patients in whom a double patch was used in order to improve the geometry of the aortic sinuses. Subsequently, Brom introduced symmetric aortoplasty that enabled the enlargement of all 3 sinuses with the use of a 3-patch technique.3,8
Supravalvular aortic stenosis is a rare disease, and most of the reported surgical series have been small. In view of the few reports on the use of Brom's technique for SVAS repair, we report here our experience with the first 9 such corrections that were performed at the Hospital de Pediatría, CMNO IMSS, Guadalajara, Jalisco, México.
From January 2002 through July 2007, 9 children (age range, 5–14 yr) underwent surgical correction of localized SVAS in our hospital. Their characteristics and pertinent clinical data are shown in Table I. All pre- and postoperative transaortic blood pressure gradients were measured by means of Doppler echocardiography and heart catheterization.
All repairs were performed by the same surgical team. All of the patients underwent median sternotomy and were maintained on cardiopulmonary bypass with moderate hypothermia, and preservation was with cold-blood cardioplegic solution. The aorta was transected several millimeters distal to the area of stenosis. A longitudinal incision was then made in each of the 3 sinuses (left of the right coronary artery, right of the left coronary artery, and centrally in the noncoronary sinus) approximately halfway down into the sinus of Valsalva, and 3 separate patches were inserted accordingly. Symmetric aortoplasty (Brom's technique)8 was used in all patients (Fig. 2). Dacron, pericardium, or both were used for the aortic repairs. All pericardia were pretreated with glutaraldehyde. A pericardial patch was used when needed for the correction of coronary artery obstruction. The enlarged proximal aortic root was then reanastomosed to the distal aorta. Postoperative evaluation by a pediatric cardiologist included Doppler echocardiography and heart catheterizations in all patients.
All of our patients' aortic valves were tricuspid, and no associated cardiac or vascular anomalies were encountered, except in patient 4, who presented with a mild aortic valve insufficiency that was not deemed clinically significant and was not repaired surgically. Only patient 1 died postoperatively, after experiencing a refractory supraventricular tachycardia. This patient had an uncorrected right coronary artery obstruction. The 3 subsequent patients with coronary artery obstruction underwent correction of the condition. The mean stay of the 8 surviving patients in the intensive care unit was 66 ± 27 hours (range, 24–96 hr). Postoperative peak blood pressure gradients were all improved (range, 0–16 mmHg) (Table I). After 6 to 55 months' follow-up (mean follow-up, 18.25 mo), none of the patients presented with new functional or anatomic alterations. As of April 2009, no reoperation was required, and all of the patients were in New York Heart Association functional class I.
The results from our series confirm that Brom's technique for SVAS repair can be used routinely. It produced good early postoperative results and lower transaortic peak blood pressure gradients than those reported previously. The improvement of anatomic repair enables the expectation of a better long-term outcome than do other methods of surgical correction.
One patient had an uncorrected right coronary artery obstruction and died postoperatively of a refractory supraventricular arrhythmia. Although no link could be established between coronary artery obstruction and arrhythmias in our patients, it is noteworthy that the 8 patients with corrected or unobstructed coronary arteries did not develop postoperative arrhythmia.
In an earlier series8 of 29 pediatric and adult patients who were operated upon for relief of SVAS, 13 underwent Brom's correction, with good results. When the investigators compared symmetric and asymmetric aortic repairs,8 the respective mortality rates were not statistically different, with a 10-year actuarial survival of 91% and no in-hospital death after 1965.8 Along with those authors and others,4 we favor Brom's symmetric approach, due to its better restoration of aortic root geometry.
In a large series of 101 patients with SVAS treated by a single group over 38 years, only 14% of the patients had Williams syndrome, and all in that subset had an associated congenital heart anomaly.11 Other reports8,12–14 showed a higher incidence of Williams syndrome (range, 28%–39%). Of note, all but 1 of our patients had Williams syndrome, and none had a substantial cardiac anomaly other than SVAS. This could be due to selection bias (for example, selective referral from other institutions, early deaths of non-Williams-syndrome patients, or inadequate diagnosis in primary-care areas), or it might indicate genetic differences, including a higher frequency of severe mutations in our patients. Williams syndrome often presents with hypercalcemia15; however, all of the children in our series had normal calcium levels.
In surgery to treat SVAS, the aim is to reduce the postoperative transaortic blood pressure gradient as much as possible. Preoperative peak gradients between 70 and 90 mmHg have been reported.16 In our series, preoperative peak gradients ranged from 28 to 72 mmHg, even though our patients were younger than were the patients in previous reports, with lower peak gradients in our older patients. Postoperative peak gradients, as reported by Flaker,14 Delius,17 and their respective colleagues, ranged from 12 to 20 mmHg in patients who underwent repair via Doty's technique; in contrast, our patients' postoperative peak gradients ranged from 0 to 16 mmHg. Indeed, 1 of our patients had a peak gradient of 0 mmHg after 24 months. Our small number of patients and short follow-up times aside, these factors encourage us to favor the 3-patch approach.
Up to 40% of patients who have undergone single-or double-patch repairs have required later operations for left ventricular outflow tract obstruction or aortic regurgitation.13,18 Although early restenosis after repair is rare, the investigators in 1 large series11 reported that 14% of patients required 1 or 2 reoperations 6 months to 30 years after having undergone correction via Doty's technique. In other series, 1 patient with localized SVAS developed diffuse restenosis,19 and Malec and associates12 reported 1 restenosis in the 20 patients whom they treated. It has been suggested that 1 component of the pathophysiology of SVAS could be the presence of elastinolytic enzymes that are secreted by smooth-muscle cells.20 Because this could contribute to further derangements in development, we have routinely performed regular follow-up hemodynamic studies in our 8 surviving patients, none of whom has needed a repeat operation thus far.
Surgical repair of SVAS in children has resulted in a reduced future need for aortic valve replacement,8,17 especially when the aortic valve is tricuspid, as was the case in all of our patients. Patch oversizing has been considered a cause of aortic regurgitation8; accordingly, all efforts should be made to improve gradients and avoid reoperation.9
Different materials have been used in SVAS repair. We used Dacron or pericardium (both, in 1 patient). Although our small number of patients does not enable meaningful comparison, we feel more comfortable with the use of pericardium alone, in terms of achieving better postoperative gradients.
In conclusion, we consider Brom's technique for SVAS repair to be safe. In our limited series, it produced effective anatomic restoration, with good short-term and potentially good long-term results.
Address for reprints: Fernando Carrillo-Llamas, MD, Av. Vallarta 1670; Guadalajara, Jal., CP 44340, México. E-mail: moc.liamtoh@lracodfrd